Summarizing 5 Years of Summarizing 5 Years of Weed Management Weed Management Research in GeorgiaResearch in Georgia

2001-20052001-2005

Eric P. Prostko

Extension Weed Specialist

and

Tim L. Grey and William K. Vencill

Research Weed Scientists

What have we done?What have we done?2001-20052001-2005

63 field trialsMajor areas of emphasis

RR corn systems LL corn systems Accent vs. Option harvest-aids tropical spiderwort

• In-crop• Post-harvest

other new products• Aim• Callisto, Lexar/Lumax

Should you use the RR corn system?Should you use the RR corn system?

advantages Inexpensive easy Broad spectrum Reduced drift concerns No soil insecticide issues

disadvantages No residual over-reliance on a single

product Herbicide resistance

concerns Volunteer in other RR crops

Texas Panicum Control At Harvest with Single Texas Panicum Control At Harvest with Single or Split Applications of Roundup WM - IIor Split Applications of Roundup WM - II

CN-04-04 (Attapulgus)

UntreatedRoundup WM @ 22 ozs/A

21 DAP

Roundup WM @ 22 ozs/A21 + 35 DAP

124

173

190

0

30

60

90

120

150

180

210

Untreated Single Split

Bu/

A

Corn Yield Response to Single or Split Applications Corn Yield Response to Single or Split Applications of glyphosate (4.5 lb ae/gal) @ 22 ozs/A.of glyphosate (4.5 lb ae/gal) @ 22 ozs/A.

Average of 6 irrigated locations (2003-05)DKC67-60RR

Glyphosate Resistance Around the WorldGlyphosate Resistance Around the World (8 species)(8 species)

rigid ryegrass (1996) goosegrass (1997) horseweed (2000) Italian ryegrass (2001) hairy fleabane (2003) buckhorn plantain (2003) common ragweed (2004) Palmer amaranth (2005)

In Central Georgia

* Can be found in US

2005 GR-Pigweed Survey

Preserving the Value of GlyphosatePreserving the Value of Glyphosate

tank-mix 2,4-D in burndown when glyphosate will be used in-cropConsider paraquat if appropriate

Alternate glyphosate use with other herbicide modes of actionTank-mix with atrazine in corn

Use other practices such as cultivation

Do not allow weed escapes to produce seed

Herbicide programs for managing Herbicide programs for managing glyphosate and ALS-resistant Palmer glyphosate and ALS-resistant Palmer amaranth in Georgia field corn.amaranth in Georgia field corn.

Corn hybrid Preemergence Postemergence Layby as needed

Conventional Prowl2 + Atrazine +Crop Oil

2,4-D5 or Evik

Conventional Bicep II Magnum3, Bullet,Guardsman, Lariat, or

Banvel4,5, Clarity5,or 2,4-D5

2,4-D5or Evik

Liberty Link Dual II Magnum6 orOutlook

Liberty + atrazine7 2,4-D5 or Evik

Roundup Ready Bicep II Magnum3, Bullet, Guardsman, Lariat, or

Lexar at 66% normal rate

glyphosate +atrazine

or Expert8

2,4-D5 or Evik

Texas Panicum ControlTexas Panicum Control

OR OR

Accent vs Option SummaryAccent vs Option SummaryTexas Panicum ControlTexas Panicum Control

8 field trials

Accent > Option 9 of 32 comparisons (28% of time)

Option > Accent 1 of 32 comparisons (3% of time)

Accent = Option 22 of 32 comparisons (69% of time)

No statistical differences in corn yield were observed in any trial!

Texas Panicum Control (104 DAT) - IITexas Panicum Control (104 DAT) - IIAccent vs Option - 2004Accent vs Option - 2004

CN-04-04 (Attapulgus)Applied 21 DAPPANTE = 1-2”, 2-4 leaf

Untreated Accent @ 0.67 ozs/AAgrioil @ 1% v/v

Option @ 1.5 ozs/AMSO @ 1.25% v/v

AMS @ 3 lbs/A

Harvest-Aid ResearchHarvest-Aid Research

Harvest-Aid - 2004Harvest-Aid - 2004

UntreatedUntreated Roundup WM @ 22 oz/ARoundup WM @ 22 oz/A Roundup WM @ 22 oz/ARoundup WM @ 22 oz/A+ Aim 2EC @ 1 oz/A + + Aim 2EC @ 1 oz/A +

COC @ 1% v/vCOC @ 1% v/v

15 DAT

Tropical spiderwort (a.k.a. Benghal dayflower)Tropical spiderwort (a.k.a. Benghal dayflower)Commelina benghalensisCommelina benghalensis

tropical Africa native annual or perennial seeds and rhizomes above and below ground

flowers 1,600 seeds/plant alternate host of southern

root-knot nematode Reservoir for southern

stem blight (white mold)

TSW in GeorgiaTSW in Georgia

* confirmed in 29 counties by GA Dept. of Ag and UGA in 2004 (blue)

* identified in 4 morecounties in 2005 (black)

Tropical Spiderwort Control in Field Corn - Tropical Spiderwort Control in Field Corn - 20052005

UntreatedUntreated(166 bu/A)(166 bu/A)

Aim 2EC @ 1.5 ozs/AAim 2EC @ 1.5 ozs/ADual Magnum 7.62EC @ 1.33 pt/ADual Magnum 7.62EC @ 1.33 pt/A

Herbimax @ 1% v/vHerbimax @ 1% v/v(168 bu/A)(168 bu/A)

34 DAT34 DAT $24/A treatment cost (excluding application)

Post-Harvest – Field CornPost-Harvest – Field Corn(Our Achilles heel?)(Our Achilles heel?)

Post-Harvest – 2005Post-Harvest – 20052,4-D (1 pt/A) + Dual Magnum (12 ozs/A) + COC (1% v/v)2,4-D (1 pt/A) + Dual Magnum (12 ozs/A) + COC (1% v/v)

22 DAT22 DAT 43 DAT43 DAT 54 DAT54 DAT

* **

Grady County $12/A Treatment cost (excluding application)

The FutureThe Future

Liberty Link?Products labeled but

not yet tested in GA Impact (AmVac)Stout (DuPont)

New products being developedKIH-485

Post-harvest for tropical spiderwort

others??

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